The proposed invention brings a significant advantage, since it allows using displacement heating (100% fresh air) for buildings. Traditional heating systems for buildings typically use recirculation eating systems (only 15% fresh air). They do not use displacement heating for buildings because producing of displacement heat for the traditional heating systems is very expensive.
Also, the proposed system is cheaper than the traditional heating systems because it includes only two apparatuses (a humidifying air recuperator and a heater), whereas a traditional system typically includes three apparatuses (a pre-heater, a re-heater, and a humidifier).
With the advent of energy crisis and an increase in the cost of energy, considerable efforts have been directed toward developing means and methods for conserving energy especially for HVAC systems. The efficient use of energy is urgently needed from an economic and ecological perspective. Energy conservation is therefore a measure for both lowering costs and protecting the environment and it can be achieved either by cutting energy use or through intelligent technical solutions like the Maisotsenko Cycle (M-Cycle). The energy-related and environmental performance of heating and humidifying systems for buildings has a great deal to do with this issue.
In winter the outside air conditions are cold and dry. As a result, there will be a continuous transfer of sensible heat as well as moisture (latent heat) from the buildings to the outside. Hence, in order to maintain required comfort conditions in the occupied space an air conditioning system is required which can offset the sensible and latent heat losses from the building. Air supplied to the conditioned space is heated and humidified in a winter air conditioning system to a required level of temperature and moisture content depending upon sensible and latent heat losses from the building.
Heating and humidification of air can be achieved through different solutions. FIG. 1 (prior art) shows the most popular such solution (scheme) along with a cycle on the psychrometric chart. As shown in FIG. 1, mixed air (a mixture of return air and outside air) is first pre-heated (process m-1 on the psychrometric chart) in a pre-heater, then humidified using a humidifier or an air washer (process 1-2) and then finally reheated in a re-heater (process 2-s). The reheated air at state ‘s’ is supplied to an air-conditioned space, for example, to a building. A flow rate of supply air should be such that when released into the building at state ‘s’, it should be able to maintain the building at state ‘I’ and offset sensible and latent heat losses (Qs and QI) (see FIG. 1).
The humidification of air can be achieved in several ways, e.g. by bringing the air in contact with a wetted surface, or with droplets of water as in an air washer, by adding aerosol sized water droplets directly to the air. When the air is humidified by contact with the wetted surface as in an air washer, the temperature of air decreases and its humidity increases due to a simultaneous transfer of sensible and latent heat. If the air washer functions as an adiabatic saturator, then humidification proceeds along a constant wet bulb temperature line. The final state of air is always obtained by applying conservation of mass (water) and conservation of energy equations to the humidification process.
During winter months, conventional heating and humidifying air systems for buildings consume a lot of energy often by burning fossil fuels. These systems are expensive and inefficient, and they include minimum three apparatuses: two heaters and one humidifier.
Also, no existing humidifier or pre-heater, or re-heater system provides a simple mechanism for adjusting the humidity level in a building. Conventional heating and humidifying air systems don't use displacement heating and humidifying (100% fresh air) for buildings. The problem with displacement heating and humidifying has always been that the treatment of outside air costs much more than the treatment of recirculated air or a mixing treatment.
With the proposed invention, this all can be changed, as it allows for an inexpensive implementation of displacement heating and humidifying processes of the outside air using only two apparatuses (instead of three, like in the known existing systems): one heater and one humidifier. As the heater it is possible to use any existing heater, but as the humidifier it is proposed to use a humidifier through the M-Cycle (for example, see the Maisotsenko et al. U.S. Pat. No. 6,497,107), which plays a critical role in managing temperature and moisture for heated and humidified air, which is directed to a building for winter time.
Therefore, the inventive humidifier (it can be named “humidifying air recuperator”) simultaneously functions as a recuperator and as a humidifier of air directed to a building. The proposed invention allows using just one device serving as an air humidifier and air recuperator instead of several devices, while having much higher thermodynamic and heat transfer characteristics.
It is desirable for any heating and humidifying system of a building in winter time to cool the exhaust air from the building as much as possible by a heat recovery process, to return more heat to the same building. It reduces consumption of heat energy for this system. The proposed invention enables reducing the temperature of exhaust air outlet from the building by utilizing the M-Cycle through the inventive humidifying air recuperator, which allows the exhaust air temperature to approach a dew point temperature of outside air.
Thus, an increase of energy consumption requires methods and systems for heating and humidifying that utilize less energy and cost and such methods and systems have been widely sought. The present invention provides a significant step forward for minimizing costs of both heating and humidifying processes. Also it provides for reduction of the peak combustion temperature and NOx level, when as the source of heat uses a natural gas burner.